3 files changed, 51 insertions, 11 deletions
diff --git a/src/arch/mips/bootblock_simple.c b/src/arch/mips/bootblock_simple.c
index 747a8bfff6..64bbae23a4 100644
--- a/src/arch/mips/bootblock_simple.c
+++ b/src/arch/mips/bootblock_simple.c
@@ -32,5 +32,7 @@ void main(void)
 	console_init();
 #endif
 
+	bootblock_mmu_init();
+
 	run_romstage();
 }
diff --git a/src/soc/imgtec/pistachio/bootblock.c b/src/soc/imgtec/pistachio/bootblock.c
index 90112646c4..1276a24153 100644
--- a/src/soc/imgtec/pistachio/bootblock.c
+++ b/src/soc/imgtec/pistachio/bootblock.c
@@ -21,6 +21,9 @@
 
 #include <stdint.h>
 #include <arch/cpu.h>
+#include <arch/mmu.h>
+#include <assert.h>
+#include <symbols.h>
 
 static void bootblock_cpu_init(void)
 {
@@ -37,3 +40,26 @@ static void bootblock_cpu_init(void)
 	/* And make sure that it starts from zero. */
 	write_c0_count(0);
 }
+
+static void bootblock_mmu_init(void)
+{
+	uint32_t null_guard_size =  1 * MiB;
+	uint32_t dram_base, dram_size;
+
+	write_c0_wired(0);
+
+	dram_base = (uint32_t)_dram;
+	dram_size = CONFIG_DRAM_SIZE_MB * MiB;
+
+	/*
+	 * To be able to catch NULL pointer dereference attempts, lets not map
+	 * memory close to zero.
+	 */
+	if (dram_base < null_guard_size) {
+		dram_base += null_guard_size;
+		dram_size -= null_guard_size;
+	}
+
+	assert(!identity_map(dram_base, dram_size));
+	assert(!identity_map((uint32_t)_sram, _sram_size));
+}
diff --git a/src/soc/imgtec/pistachio/include/soc/memlayout.ld b/src/soc/imgtec/pistachio/include/soc/memlayout.ld
index 5b50a0a365..802592f4d5 100644
--- a/src/soc/imgtec/pistachio/include/soc/memlayout.ld
+++ b/src/soc/imgtec/pistachio/include/soc/memlayout.ld
@@ -23,20 +23,32 @@
 
 SECTIONS
 {
-	DRAM_START(0x80000000)
-	RAMSTAGE(0x80000000, 128K)
+	/*
+	 * All of DRAM (other than the DMA coherent area) is accessed through
+	 * the identity mapping.
+	 */
+	DRAM_START(0x00000000)
+	/* DMA coherent area: accessed via KSEG1. */
+	DMA_COHERENT(0x00100000, 1M)
+	POSTRAM_CBFS_CACHE(0x00200000, 128K)
+	RAMSTAGE(0x00220000, 128K)
 
-	/* GRAM becomes the SRAM. */
-	SRAM_START(0x9a000000)
+	/*
+	 * GRAM becomes the SRAM.  Accessed through KSEG0 in the bootblock
+	 * and then through the identity mapping in ROM stage.
+	 */
+	SRAM_START(0x1a000000)
+	ROMSTAGE(0x1a004800, 36K)
+	PRERAM_CBFS_CACHE(0x1a00d800, 74K)
+	SRAM_END(0x1a020000)
+
+	/* Bootblock executes out of KSEG0 and sets up the identity mapping. */
 	BOOTBLOCK(0x9a000000, 18K)
-	ROMSTAGE(0x9a004800, 36K)
-	CBFS_CACHE(0x9a00d800, 74K)
-	SRAM_END(0x9a020000)
 
-	/* Let's use SRAM for stack and CBMEM console. */
+	/*
+	 * Let's use SRAM for stack and CBMEM console.  Always accessed
+	 * through KSEG0.
+	 */
 	STACK(0x9b000000, 8K)
 	PRERAM_CBMEM_CONSOLE(0x9b002000, 8K)
-
-	/* DMA coherent area: end of available DRAM, uncached */
-	DMA_COHERENT(0xAFF00000, 1M)
 }